The present invention relates to improvements to a highway crash cushion of the type having an array of diaphragms, a plurality of energy absorbing elements disposed between the diaphragms, and an array of fender panels extending alongside the diaphragms.
Highway crash cushions of this general type have proven to be successful in a wide variety of applications. Walker U.S. Pat. No. 3,982,734 describes one early version of such a crash cushion, and Meinzer U.S. Pat. No. 4,321,989 discloses another. Typically, such crash cushions are used alongside highways in front of obstructions such as concrete walls, toll booths and the like.
In the event of an axial impact, the crash cushion is designed to absorb the kinetic energy of an impacting vehicle as the crash cushion collapses axially. In such an axial collapse, the diaphragms move closer to one another, the fender panels telescope over one another, and the energy absorbing elements are compressed. After such a collision many of the component parts can be reused by repositioning the diaphragms and fender panels in the original position, and replacing the energy absorbing elements and other damaged components.
The performance of such a highway crash cushion in lateral rather than axial impacts is also significant. When an impacting vehicle strikes the fender panels obliquely, it is desirable that the crash cushion act as a guard rail, which redirects the impacting vehicle without sending it back into traffic at a steep angle, and without allowing the impacting vehicle to move into the region on the other side of the crash cushion protected by the crash cushion.
Another aspect of such crash cushions is the need for simple maintenance and repair. Typically, such crash cushions are positioned alongside a high speed roadway, and it is therefore important to minimize traffic disruption and to minimize exposure of maintenance personnel to the hazards of adjacent traffic in maintenance and repair procedures.
In view of the foregoing operational and maintenance requirements for crash cushions, there is a need for an improved crash cushion that provides increased rigidity in a lateral impact, that decelerates an impacting vehicle in a more controlled manner in a lateral impact, both when the vehicle is moving along the fender panels in a forward and in a reverse direction, and to provide a crash cushion which is simpler to install and easier to maintain.